| #define _GNU_SOURCE |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include <netdb.h> |
| #include <inttypes.h> |
| #include <errno.h> |
| #include <string.h> |
| |
| int getservbyport_r(int port, const char *prots, |
| struct servent *se, char *buf, size_t buflen, struct servent **res) |
| { |
| int i; |
| struct sockaddr_in sin = { |
| .sin_family = AF_INET, |
| .sin_port = port, |
| }; |
| |
| /* Align buffer */ |
| i = (uintptr_t)buf & sizeof(char *)-1; |
| if (!i) i = sizeof(char *); |
| if (buflen < 3*sizeof(char *)-i) { |
| errno = ERANGE; |
| return -1; |
| } |
| buf += sizeof(char *)-i; |
| buflen -= sizeof(char *)-i; |
| |
| if (strcmp(prots, "tcp") && strcmp(prots, "udp")) return -1; |
| |
| se->s_port = port; |
| se->s_proto = (char *)prots; |
| se->s_aliases = (void *)buf; |
| buf += 2*sizeof(char *); |
| buflen -= 2*sizeof(char *); |
| se->s_aliases[1] = 0; |
| se->s_aliases[0] = se->s_name = buf; |
| |
| if (getnameinfo((void *)&sin, sizeof sin, 0, 0, buf, buflen, |
| strcmp(prots, "udp") ? 0 : NI_DGRAM) < 0) return -1; |
| |
| *res = se; |
| return 0; |
| } |